It's a myth. It rarely ever happens as men in the military are usually very very straight. Those who aren't keep quiet about it because they don't want to get made fun of. I'm sure there are men in the military who have sex with each other, but it is probably not during peacetime and not where anyone finds out.
Sure, it's in the glory hole trailer. it's located between the male latrine trailer and the female shower trailer. Make sure you check the posted cleaning hours before going in, the floor is sticky, i hear.